Candies, confections and snack foods are consumed for their eating enjoyment. The food properties responsible for giving the enjoyable sensation, the tastes, aromas and textures are often measured as a group often referred to as the organoleptic property of a food composition. This global measurement can be defined by quantitative sensory value, defined as likability or acceptability. The value is the sum total of sensory perception of the food as determined by trained experts who taste the food. While the measurement of likability or acceptability may appear subjective, when done under controlled conditions and with scientific methods, these measures can be determined with great precision and accuracy. In the food industry, the overall sensory likability or acceptability is used as a prediction of the commercial success of a new product and is the basis for multi-million dollar decisions regarding the product introduction.
The fat and oil components of most confectionery products greatly influence the perception of quality and overall likability or acceptability. The fats and oils become part of the system as a constituent of raw materials, such as cocoa beans, milk and the like. When nuts, such as peanuts, are added to the confectionery, the fats and oils therein also become part of the system.
The peanuts, when added to chocolate confectioneries, are usually processed, i.e., roasted. Thus, chocolate confectioneries which contain peanuts contain the fat and oil mixture normally found in the chocolate as well as the fat and oil normally found in roasted peanuts.
Roasting in air or oil is a necessary part of peanut processing and provides a taste which the public enjoys in peanut-containing chocolate confections. Without roasting, the peanuts in these products would taste beany.
Concomitant with roasting are various consequences, some beneficial, others detrimental.
Besides providing for the roasted peanut flavor, roasting serves to destroy enzymes, which, if left intact, would cause enzymatic oxidation of the product. For example, lipoxygenase, which directly adds molecular oxygen to unsaturated fatty acids and helps promote oxidation of the oil, is rapidly destroyed by roasting. So are other hydrolyric enzymes. A thorough roasting is essential to denature harmful enzymes.
On the other hand, roasting has negative consequences. For example, unroasted peanuts contain chemicals having anti-oxidant properties which act to protect the oil. However, in the roasting process, these chemicals become oxidized.
In addition, roasting also destroys potentially beneficial enzymes, such as superoxide dismutase, which is thought to act as a natural antioxidant.
Roasting also disrupts cellular compartmentalization of the oil within the peanut. Oil is normally found in oil bodies. These are expanded and agglomerated during the roasting process. This allows the oil to come in contact with the myriad of other chemicals found within the peanut-some chemicals of biological origin and some from other sources. It also delocalizes the peanut oils, such that migration into other phases of the product composition can more readily occur.
Processed peanut-containing confections suffer from a rapid decline in acceptability over time compared with confections which do not contain peanuts. For example, chocolate candies containing peanuts, peanut brittle or peanut butter can have shelf lives of approximately eight months or less. By comparison, the shelf life of solid milk chocolate is beyond one year. Processed peanuts turn rancid in these foods, as a result of oxidation, causing the chocolate confectionery product to have an unpleasant taste.
The modes of product failure in these processed peanut containing products are multiple. The loss of the characteristic fresh-roasted peanut taste and aroma is termed flavor fade. Associated with flavor fade is the general loss of desirable roasted nut flavor and the reappearance of unpleasant raw beany flavor chemicals. These changes are thought to result from the oxidation or hydrolysis of fresh roasted peanut flavors. Coincident with product aging is the direct oxidation of the peanut oil. The oxidation of oils results in the characteristic appearance of cardboardy, painty, fishy or rancid flavors which occur as the oil is oxidized to peroxides which decompose into secondary oxidation products, such as hydrocarbons, aldehydes and other strongly flavored chemicals. The combination of flavor fade and the oxidation of oils reduces the product likability or acceptability and provides the consumer with an unpleasant eating experience to the point where products are no longer salable. Hence, a short shelf life is generally characteristic for processed peanut products. When these out of date goods are returned, they must be destroyed. This short shelf life also results in generally high rates of consumer complaints for these products because off-flavors develop at a faster rate in products which contain processed peanuts.
Chocolate products contain a relatively high level of fats and oils. In these chocolate confections containing processed peanuts, because the oil based chemicals causing off-flavors in the peanut are more readily oxidized, the prospects for cross-contamination of the chocolate fats and oils is markedly enhanced.
Thus, the problems described hereinabove with chocolate confections containing peanuts have plagued and continue to plague the confectionery industry. The chocolate industry is actively trying to find solutions, but unfortunately, no one has been successful in finding a solution for prolonging the shelf life of confections containing peanuts. The search still continues for a viable solution.
There are various means that have been utilized to avoid oxidative rancidity which have been implemented in peanut products, including peanut containing snacks.
For example, refining the oil to remove pro-oxidant metal cations such as Cu.sup.2+, Cu.sup.1+, or Fe.sup.2+, Fe.sup.+3 that are present in the peanut oil, the addition of antioxidants, deaeration of the oil, nitrogen flushing, storage under inert gas, vacuum packaging and hydrogenation are all known to improve the keeping qualities of peanut oil. Options for improving the shelf life of peanut butter are somewhat more limited, but include deaeration, inert gas flushing and vacuum packing. With whole or substantially intact processed peanuts, the range of options to extend shelf life narrows further. The main means for extending the shelf life of peanut products are deaeration, vacuum packing and inert gas flushing.
However, these means are not viable or practical to chocolate confectioneries containing peanuts. Refining of oils removes all but the most subtle of flavors and results in a bland product virtually free of the flavors one would recognize in peanut confections and snacks. In confections and other processed peanut snacks, the removal of metal ions and hydrogenation are not options because these strategies require the removal of the oil from the peanut followed by reincorporation of peanut oil into the peanut. Oil removal destroys the flavor, texture and shape of the peanut. Hydrogenation changes the flavor and mouthfeel of oils. In addition, with candies and certain snacks, nitrogen flushing, deaeration and vacuum packing have practical limitations. These strategies rely upon a hermetically sealed, oxygen impermeable packaging. The current state of packaging of confections and other snacks often do not allow for the added expense of barrier packaging materials nor do they permit the slower production speeds required for hermetic sealing. Obviously, processed peanut-containing confections cannot be packed in glass, plastic or cans as are typical for peanut oil or peanut butter--the cost of the package and its disposal after use are much too expensive. For the present, virtually all processed peanut-containing confections are packaged in oxygen permeable packages.
The present inventors, however, have provided a solution to the problem; they have developed a chocolate confectionery article containing peanuts having a high oleic content. These chocolate confections have a continuous fat based chocolate phase and a discontinuous peanut phase in which the peanut therein consists of high oleic acid peanuts. The inventors thus have replaced the normal peanuts found in chocolate confectioneries with peanuts having high oleic acid content. As the inventors have discovered, the oil of these peanuts having a high oleic acid content extend the shelf life of these chocolate confections because they contain a lower amount of unsaturated fatty acid in the oil.
Typical peanuts contain an oil composition which is summarized below for Sunrunner peanuts as representative:
______________________________________ Fatty Acid (# of Carbon Atoms: # of double bonds) % of Total Fat ______________________________________ 16:0 9.40 16:1 0.07 17:0 0.07 17:1 0.07 18:0 1.95 18:1 49.05 18:2 30.40 18:3 0.00 20:0 1.26 22:0 3.77 22:1 0.10 24:0 2.39 ______________________________________
Oxidation of peanut oil requires oxidation of the double bonds in peanut oil. Since peanut oil contains a relatively high complement of linoleic acid (18:2), a polyunsaturated fatty acid, it is inherently more unstable than many other vegetable oils which do not contain as much linoleic acid. Peanut oil is especially susceptible to oxidative rancidity due to the amount of unsaturation contained therein.
Thus, in order to reduce the oxidative rancidity of the peanuts in chocolate confections, the present inventors developed a peanut containing chocolate confection in which the amount of linoleic acid is dramatically reduced and the amount of oleic acid is significantly increased so that the peanut contains a high oleic acid content.
High oleic acid-containing peanuts are known. Norden et al. in an article entitled "Variability in Oil Quality Among Peanut Genotypes in the Florida Breeding Program," (1987) Peanut Science 14:7-11 (hereinafter "Norden et al."), discovered a naturally occurring mutant of Spanish Peanut. This peanut was characterized by having a highly modified oil composition in which the linoleic acid content was reduced to less than 4% compared to approximately 30% for typical runner peanuts. Concomitantly, the oleic acid content of this peanut mutant increased to over 78% compared to the 48% to 50% typically seen in runner peanuts. This new line of peanuts was designated line F435-2--1 and F435-2--2.
Peanuts of either Norden's mutant F435 or a genetic derivative were used by O'Keefe et al. as described in the article entitled "Comparison of Oxidative Stability of High and Normal Oleic Peanut Oils, (1993) JAOCS 70(5):489-492, to produce a high oleic peanut oil. The oil used by O'Keefe et al. was solvent extracted from unroasted peanuts, refined by caustic refining, and water washed to remove undesirable compounds from the oil. This oil would be expected to be bland and flavorless. This oil was almost entirely composed of triglycerides and is a much more defined and predicmable food system than whole, roasted peanuts. The high oleic peanut oil was found to be more resistant to oxidation than the oil from normal peanuts.
The F435 line was also used by Cammar et al. as described in Canadian Patent Application No. 2020564. The investigators therein described peanut butter as fine particles of peanut suspended in a continuous oil phase. Cammar et al. recognized that to produce the desired product texture, spreadability, mouthfeel and other desired properties of peanut butter, it was necessary to finely grind the roasted peanuts to release the peanut oil and to reduce the intact peanut particles to very small sizes. They found the resulting peanut butter to be more stable than the peanut butter made from regular peanuts.
Although the Canadian Patent Application suggests that the peanut butter therein could be used in "confections and snacks," there is no specific teaching or suggestion therein that the peanut butter could be used in chocolate confections. There are various types of confections, such as sugar confections, baked confections and fruit confections. Sugar confections, in turn, consist of two classes, amorphous and crystalline, which themselves are divided into several groups, e.g., hard candy, brittles, taffies, toffees, jellies, gums, fondants, creams, pralines, fudges, chocolates, nougats, pressed candy, marzipan, pastes, panned candies, and the like. The present invention is drawn to chocolate confections which fall in the category of crystalline which are fat-based, having a continuous fat-based chocolate phase and a discontinuous peanut phase.
Furthermore, for many processed peanut confections and snacks, the deliberate release of peanut oil, as taught in the Canadian Patent Application, is highly undesirable. In roasted peanut chocolate confections, the release of peanut oil promotes fat bloom in chocolate, softens the texture of chocolate, can cause puddling of free oil and will result in more rapid oxidation of an already short shelf life product. In whole roasted peanuts, release of free oil will cause objectionable surface appearance and textural changes in the food. Of course when chocolate confections are prepared containing chopped peanuts or parts of the peanuts, there will be some release of peanut oil into the chocolate. However, the present invention minimizes the interaction of linoleic acid in the peanut oil with the chocolate, thereby reducing the amount of oxidation of same.
Furthermore, although the oil containing a higher amount of oleic acid may be more stable, there is no predictability of the stability of the confection based upon oil compositions. As Yuki, et al., in an article entitled "Oxidative Deterioration of Roasted Peanuts", in Journal of Japanese Society of Food Science and Technology 1978, 5, 293-301, teach, there is no predictability of whole peanut stability based upon oil composition. Since the peanut is being placed in a complex matrix such as chocolate confections, the stability of the peanut in this environment is totally unpredictable.
Moreover, the effect of the interaction of the high oleic acid peanut with the chocolate in the confection of the present invention is also unpredictable. For example, prior to the present invention, the effect of the release of peanut oil comprised of high oleic acid on the chocolate was unknown. The compatibility of this peanut oil with the chocolate has never been investigated. A priori, before preparing a chocolate confection containing high oleic peanuts, there is no way to predict the effect of the oil on the chocolate. It might have the same effect or have more detrimental effects on the chocolate than peanut oil made from regular peanuts.
Heretofore, prior to the present invention, no one had specifically suggested that high oleic peanuts, whole or in part, including chopped and finely divided peanuts or parts thereof or peanut butter could be used in chocolate confections, even though it has been eight years since the publication of Norden et al. When the present inventors, however, had prepared chocolate confections using peanuts of high oleic acid, they had unexpectedly found that the products were significantly more stable than the chocolate products containing regular peanuts and significantly more stable than predicted by calculation of the composite oil fatty acid composition.